/Engine/Source/Runtime/Analytics/Analytics/Public/AnalyticsEventAttribute.h
Hack to allow assignment. This class only "sort of" acts like an immutable class because the const members prevents assignment, which was not intended when this code was changed.
[FAnalyticsEventAttribute](API\Runtime\Analytics\FAnalyticsEventAttribute) & operator= ( [FAnalyticsEventAttribute](API\Runtime\Analytics\FAnalyticsEventAttribute) && RHS )